Peavey XR600C...

[Perseus]

Hello,
I'm working on a Peavey XR600c with a 400BH power amp. I plug the mic(an SM58 clone) into the low Z jack and all I get is a very faint thud at high levels.
I am running a speaker cable from the back jack to the cabinet (happen to have a 200 watt 8 ohm Ampeg cab in the room).

I read the other threads and plugged an ipod into the power amp section, then ran speaker cable from the main out to a practice amp, and it did play. Ran the cable from the back speaker out with the ipod still in the power amp and it played loudly through the Ampeg cabinet.

So, I gather the pre-amp is okay and the power amp is okay, so any suggestions on why I can't get mic volume?

Thanks,

Jeremy

[Enzo]

Does this mic not work in ANY of the XLR input jacks? Or just one? Does this mic work when plugged into some other system? Each channel also has a line level input. Do those work? Plug your signal into each channel input jack, do you get sound out that way?


SM58 clone? Does that mean it looks like one, a wind ball mic?

[Perseus]

Right, it does not work in any of the 6 xlr jacks. I cleaned the connections and tested each one, only getting a faint thumping through the speaker when I tap the mic. The mic and cable brand is OSP, similar to the SM58, and yes, a ball mic. I will write back after work when I can test the high Z line input with the ipod. Thanks,

Jeremy

[Perseus]

Okay, I tested each channel's high z 1/4" input with a music signal from the ipod. I could hear the music play through the speaker, but it was faint as well, even at top volumes all around (channel volumes, master volumes and device volume). But, now that I've done that, it reminds me of what I heard coming out of the main out into the other amp. I thought the practice amp was not performing because of its size, but might it be the pre-amp? Thanks,

Jeremy

[Enzo]

OK, so it is ANY input, not just a mic input. None of the input channels pushes a strong output signal. And the power amp works we know. That narrows it down to the master section. I would first suspect an op amp in that area.

PV will send you the schematics if you request them.

[Perseus]

Right. I will request the schematics. Thanks,

Jeremy

[Perseus]

So, a week later...

Three calls to Peavey, with two different email providers (gmail and yahoo) given, an email request as well, and still nothing. Starting to get really annoyed with Peavey.

How do I get the schematic?

Thanks,

Jeremy

[Enzo]

WHo did you talk to? Normally customer service at Peavey will do everything but buy you lunch.

[Perseus]

So I've heard. They just keep saying,

PV: "I can email it to you"
Me: "Sure. Great."
PV: "What's your email address"
Me: gives email address
PV: "Okay, it's on the way"

Whatever that means, because it never gets there. I guess I'll have to make them read back the email address to me. I'll give it a try Monday...

[Perseus]

I recant...
The email was the best method. I now have the schematic (though it took a week, but no worries).

I'll start looking for an op amp in the master section. I assume that means "output" amp, right? So, I need to check all outputs with a meter?

[Enzo]

The preamp panel comprises a channel board and a master board. I think your op amps are all in sockets anyway. On the master board, just go down the row of parts and check pins 1 and 7 of each op amp. The op amps are the little 8-legged ICs scattered about. We expect NPT to see DC voltages there.

let me start anew. YOu say you have solid output from the MAIN out if sent to another amp? Plug a spare cord from MAIN OUT right into POWER AMP IN. if this restores the sound, rep[lace the powr amp jack. if not, try patching Main out and graphic in together, and if that is no help, patch grqphic out and power amp in together. If any of that restores the sound, the inoput jack of the pair will be at fault.